1.Core Concepts

Create a namespace called 'mynamespace' and a pod with image nginx called nginx on this namespace

$ kubectl create namespace mynamespace
$ kubectl get ns
NAME                   STATUS   AGE
mynamespace            Active   6m13s

$ kubectl run nginx --image=nginx --restart=Never -n mynamespace
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          5m2s

Create the pod that was just described using YAML

kubectl run nginx --image=nginx --restart=Never --dry-run=client -n mynamespace -o yaml > pod.yaml

cat pod.yaml

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: nginx
  name: nginx
spec:
  containers:
  - image: nginx
    name: nginx
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Never
status: {}

delete old nginx pod and recreate one

kubectl delete po nginx -n mynamespace
kubectl create -f pod.yaml -n mynamespace

Alternatively, you can run in one line

kubectl run nginx --image=nginx --restart=Never --dry-run=client -o yaml | kubectl create -n mynamespace -f -

 

Create a busybox pod (using kubectl command) that runs the command "env". Run it and see the output

$ kubectl run busybox --image=busybox --command --restart=Never -it -- env
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=busybox
TERM=xterm
KUBERNETES_PORT=tcp://10.244.64.1:443
KUBERNETES_PORT_443_TCP=tcp://10.244.64.1:443
KUBERNETES_PORT_443_TCP_PROTO=tcp
KUBERNETES_PORT_443_TCP_PORT=443
KUBERNETES_PORT_443_TCP_ADDR=10.244.64.1
KUBERNETES_SERVICE_HOST=10.244.64.1
KUBERNETES_SERVICE_PORT=443
KUBERNETES_SERVICE_PORT_HTTPS=443
HOME=/root

$  kubectl run busybox --image=busybox --command --restart=Never -- env
pod/busybox created

$ kubectl logs busybox
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=busybox
KUBERNETES_PORT_443_TCP_PROTO=tcp
KUBERNETES_PORT_443_TCP_PORT=443
KUBERNETES_PORT_443_TCP_ADDR=10.244.64.1
KUBERNETES_SERVICE_HOST=10.244.64.1
KUBERNETES_SERVICE_PORT=443
KUBERNETES_SERVICE_PORT_HTTPS=443
KUBERNETES_PORT=tcp://10.244.64.1:443
KUBERNETES_PORT_443_TCP=tcp://10.244.64.1:443
HOME=/root

 

Create a busybox pod (using YAML) that runs the command "env". Run it and see the output

$ kubectl run busybox --image=busybox --restart=Never --dry-run=client -o yaml --command -- env > envpod.yaml

$ cat envpod.yam
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: busybox
  name: busybox
spec:
  containers:
  - command:
    - env
    image: busybox
    name: busybox
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Never
status: {}

$ kubectl apply -f envpod.yaml
pod/busybox created

# kubectl logs busybox
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=busybox
KUBERNETES_SERVICE_PORT_HTTPS=443
KUBERNETES_PORT=tcp://10.244.64.1:443
KUBERNETES_PORT_443_TCP=tcp://10.244.64.1:443
KUBERNETES_PORT_443_TCP_PROTO=tcp
KUBERNETES_PORT_443_TCP_PORT=443
KUBERNETES_PORT_443_TCP_ADDR=10.244.64.1
KUBERNETES_SERVICE_HOST=10.244.64.1
KUBERNETES_SERVICE_PORT=443
HOME=/root

 

Get the YAML for a new namespace called 'myns' without creating it

# kubectl create namespace myns -o yaml --dry-run=client
apiVersion: v1
kind: Namespace
metadata:
  creationTimestamp: null
  name: myns
spec: {}
status: {}

 

Get the YAML for a new ResourceQuota called 'myrq' with hard limits of 1 CPU, 1G memory and 2 pods without creating it

 

 

 

 

 

 

Create a busybox pod (using kubectl command) that runs the command "env". Run it and see the output

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Create a busybox pod (using YAML) that runs the command "env". Run it and see the output

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Get the YAML for a new namespace called 'myns' without creating it

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Get the YAML for a new ResourceQuota called 'myrq' with hard limits of 1 CPU, 1G memory and 2 pods without creating it

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Get pods on all namespaces

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Create a pod with image nginx called nginx and expose traffic on port 80

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Change pod's image to nginx:1.7.1. Observe that the container will be restarted as soon as the image gets pulled

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Get nginx pod's ip created in previous step, use a temp busybox image to wget its '/'

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Get pod's YAML

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Get information about the pod, including details about potential issues (e.g. pod hasn't started)

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Get pod logs

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If pod crashed and restarted, get logs about the previous instance

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Execute a simple shell on the nginx pod

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Create a busybox pod that echoes 'hello world' and then exits

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Do the same, but have the pod deleted automatically when it's completed

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Create an nginx pod and set an env value as 'var1=val1'. Check the env value existence within the pod

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